ISO Three-Pass Mutual Authentication Protocol with CCFs (Cryptographic Check Functions)

Purpose

The keyed function fKab(X) returns hashed value for data X in a manner determined by the key Kab.

Informal Specification

  1. B -> A: Rb,Text1
  2. A -> B: Ra, Text3, fKab(Ra,Rb,B,text2)
  3. B -> A: Text5, fKab(Rb,Ra,A,text4)

See Commonly Used Representations

MSR Specification

Click here to download 
--- Author: rishav
--- Date: 16 December 2007
--- ISO Three-Pass Mutual Authentication Protocol with CCFs
---
---	  B -> A: Rb,Text1
---       A -> B: Ra, Text3, fKab(Ra,Rb,B,text2)
---       B -> A: Text5, fKab(Rb,Ra,A,text4)
(reset)
(
module ISOPublicThreePassMutual
export * .

key : type.
shrk : princ -> princ -> type.          shrk A B <: key.
randomNo: type.                           randomNo  <: msg.

f : key -> msg -> msg.
text: type.				text <: msg.

net : msg -> state.

initiator:
forall B : princ.
{
 		exists LB : randomNo -> state.

 ISO3initRule1:
    forall text1 : text.
    empty
  => exists Rb : randomNo.
    net(Rb & text1), LB Rb.

 ISO3initRule3:
  forall A : princ.
  forall Rb : randomNo.
  forall Ra : randomNo.
  forall Kab : shrk A B.
  forall text3 : text.
  forall text2 : text.
  forall text4 : text.
  forall text5 : text.
     net(Ra & text3 & f Kab (Ra & Rb & B & text2)), LB Rb
  => net(text5 & f Kab (Rb & Ra & text4)).
}


reciever:
forall A : princ.
{
				exists LA : princ -> randomNo -> randomNo -> state.
  ISO3initRule2:
  forall B : princ.
  forall Rb : randomNo.
  forall Kab : shrk A B.
  forall text3 : text.
  forall text2 : text.
  forall text1 : text.
   net(Rb & text1)
  =>exists Ra : randomNo. 
   net(Ra & text3 & f Kab (Ra & Rb & B & text2)), LA B Ra Rb.

  ISO3initRule4:
  forall B : princ.
  forall Rb : randomNo.
  forall Ra : randomNo.
  forall text4 : text.
  forall text5 : text.
    net(text5 & f Kab (Rb & Ra & text4)), LA B Ra Rb
  => empty.
}
)